In the States,standard extra fuel when thunderstorms are forecast is one hour and that includes a tempo observation.
Thunderstorms do,however,tend to be more spectacular stateside.
This thread is important and it should be allowed to run its course.I wonder how many UK pilots feel:
a)that their company encourage a minimum fuel policy to the extent that if they request extra,and it is subsequently proven to be unwarranted,that they will in some way be sanctioned?
b)that their chief pilot wears a corporate hat too often?A good CP dances to only one tune:"How can I best help my pilots to attain the safest operation possible?"He knows each and every pilot,their weaknesses,their strengths.And above all,trust is implicit.Its a managerial role,yes,but never a corporate one.Let the ops director try and bridge the gap between economics and safety.